An error occurred in the article by Chaffee BW et al, titled “Electronic Cigarette Use and Progression From Experimentation to Established Smoking” published in the April 2018 issue of Pediatrics (2018;141[4]: e20173594; doi:10.1542/peds.2017-3594). On page 3, in Table 1, under the heading “Outcome: smoked 100 cigarettes and smoked during the past 30 d” and the row “E-cigarette former,” the unweighted number of participants (n) reads: “406.” This should have read: “404.”